A Free-Market Energy Blog

The Brave Judith Curry (one plus the truth equals a majority)

By Robert Bradley Jr. -- May 6, 2015

Those interested in energy and climate policy should subscribe to Climate, Etc., hosted by Judith Curry, the fearless one-woman truth seeker in the polarized climate debate. Professor Curry, who is very well credentialed — and respected by the quiet climatologists, not only the so-called skeptics — is arguably the most important voice in the physical science side of today’s climate debate. Not only is her research at the cutting edge of the unsettled science, she regularly, accurately, and fearlessly reports the latest in the science debates

Professor Curry recently testified before the House Committee on Science, Space and Technology, which held a hearing, “The President’s UN Climate Pledge: Scientifically Justified or a New Tax on Americans?” She then answered follow-up questions, from which the indented answers are drawn. (Note: the bold headings are mine and not questions from the Committee–those can be found in her entire response.)

Temperature Impact of Obama’s CO2 Aspirational Goal

If you believe the climate models, then President Obama’s INDC commitment (total of 80% emissions reduction by 2015), then warming would be reduced by 0.011 degrees Centigrade, a number that was provided to me by Chip Knappenberger of CATO using the MAGICC model with an equilibrium climate sensitivity of 3.0oC http://www.cato.org/blog/002degc-temperature-rise-averted-vital-number-missing-epas-numbers-fact-sheet. If the climate models are indeed running too hot, then the warming would be reduced by an even smaller number. 

Temperature Impact w/o U.S. Greenhouse Gas Emissions

Eliminating all U.S. greenhouse gas emissions by 2050 would reduce the warming by 0.014oC (as per the EPA MAGICC model).   This is an amount of warming that is much smaller than the uncertainty in even measuring the global average temperature.

Bias from Climate Change Orthodoxy

The censure of scientists disagreeing with the IPCC consensus was particularly acute during the period 2005-2010. As revealed by the Climategate emails, there was a cadre of leading climate scientists that were working to sabotage the reviews of skeptical research papers (and presumably proposals for research funding). Further, scientists challenging climate change orthodoxy are subjected to vitriolic treatment in news articles, op-eds and blogs, damaging the public reputation of these scientists. I have heard from numerous scientists who are sympathetic to my efforts in challenging climate change orthodoxy, but are afraid to speak out or even publish skeptical research since they are fearful of losing their job.

Since 2010, things have improved somewhat especially in Europe; I think this has largely been due to reflections following Climategate and the fact that disagreement about climate change is not as starkly divided along the lines of political parties (i.e. the issue is somewhat less politicized). In the U.S., with President Obama’s recent pronouncements about climate denial and climate deniers (as anyone who does not agree with the consensus) has increased the toxicity of the environment (both academic and public) for scientists that question the IPCC consensus on climate change.

Climate Model Overwarming/Problems

Particularly for the past decade, climate models have been running too hot, predicting more warming than has been observed (refer to the figure on page 6 of my testimony http://www.climate-lab-book.ac.uk/comparing-cmip5-observations/.

The discrepancies between observed surface temperatures and climate model simulations indicates that climate models are not useful for predicting climate on decadal time scales (out to 20 years) or for regional spatial scales. If the so-called warming hiatus continues for another few years, then the observations will be completely outside of the envelope of climate model predictions.

I have argued that climate models are not fit for the purpose of simulating decadal scale and regional climate variability. Climate models are mainly useful for scientific exploration of mechanisms in the climate system. Whether they are at all useful for projections of century scale climate change remains to be seen, but I am doubtful.

Lower-Sensitivity Modeling?

For the main climate models used in the CMIP5 simulations for the IPCC AR5, climate sensitivity is an emergent property and not one that is easily tuned. For simpler climate models, such as MAGICC http://www.cgd.ucar.edu/cas/wigley/magicc/, climate sensitivity can be tuned, see http://www.cato.org/blog/002degc-temperature-rise-averted-vital-number-missing-epas-numbers-fact-sheet

Natural Climate Variability/Gaps in Knowledge

  • Solar impacts on climate (including indirect effects).  What are the magnitudes and nature of the range of physical mechanisms?

  • Nature and mechanisms of multi-decadal and century scale natural internal variability.  How do these modes of internal variability interact with external forcing, and to what extent are these modes separable from externally forced climate change?

  • Deep ocean heat content variations and mechanisms of vertical heat transfer between the surface and deep ocean.

  • The strength of carbon cycle feedbacks (both land and ocean)

  • Climate dynamics of clouds: Could changes in cloud distribution or optical properties contribute to the global surface temperature hiatus? How do cloud patterns (and TOA and surface radiative fluxes) change with shifts in in atmospheric circulation and teleconnection regimes (e.g. AO, NAO, PDO)? How do feedbacks between clouds, surface temperature, and atmospheric thermodynamics/circulations interact with global warming and the atmospheric circulation and teleconnection regimes?

Overarching Uncertainties

  • Whether the warming since 1950 has been dominated by human causes

  • How much the planet will warm in the 21st century …

  • Sensitivity of the climate system to external forcing, including fast thermodynamic feedbacks (water vapor, clouds, lapse rate).

IPCC Climate Sensitivity Trends

Since the IPCC AR4 in 2007, both the upper bound (at the very likely level) and lower bound (at the likely level) to climate sensitivity have been lowered. There is a dichotomy between climate model estimates (higher) and observation based estimates (lower)….

Under the Business As Usual Emissions Scenario (RCP8.5), the IPCC AR5 projects a likely increase of global mean surface temperatures for 2081–2100 relative to 1986–2005 to be 2.6°C to 4.8°C (RCP8.5). The likely confidence implies that there is a 34% chance that the increase could lie outside this range. Personally, I think the IPCC is overconfident in their estimate; I would expect the warming to lie below this range.

Likely Climate Sensitivity

The most recent estimates from observations suggest a transient climate response of 1.05 to 1.45 oC and equilibrium climate sensitivity of 1.2 to 1.8 oC [17-83% range]…

For the past decade, global surface temperatures have been running cooler than the model projections. The lack of recent warming appears to be caused by changes in ocean circulations in the Pacific and Atlantic Oceans, with perhaps some contribution from the sun.

Extreme Weather and Climate Policy

Extreme weather and climate events have always occurred and will continue to occur. Further, sea level has been rising since the last ice age. Even if you believe the climate models and the IPCC assessment and we are successful at eliminating CO2 emissions, we would not expect to notice any significant difference in extreme events at the end of the 21st century. Measures to reduce our vulnerability to weather and climate extremes make sense whether or not humans are influencing climate in any significant way.

Obama Climate ‘Insurance’ Policy?

If we are to view climate mitigation policies as an insurance policy, the cost of the policy needs to be commensurate with the possible damage, and the policy has to actually be effective at shielding the policy holder from losses….

The President’s INDC is not a good insurance policy, as per the above criteria.

The 2oC Warming Threshold

The concern about inaction comes from concern about passing the 2oC ‘danger’ threshold, possibly by mid-century. This concern relies on a very weak assessment that 2oC of warming is actually ‘dangerous’ and that we can believe the climate models (which seem to be running too hot).


  1. Harry Dale Huffman  

    Judith Curry is an academic, and so retains her faith in the basic science–especially, the so-called “greenhouse effect” of increasing global mean surface temperature (GMST) with increasing atmospheric carbon dioxide, CO2 (which should not be confused with the air pollutants, carbon MONoxide, CO, and elementary, i.e., black, fine carbon aerosol particles, C–but it is so confused, that is, lied about by no less than the President of the United States and the entire political Left, having been outlawed as an official “pollutant” itself, when it is not). The “greenhouse effect” is enshrined in the climate models, whence her discussion of the “climate sensitivity” of the atmosphere to increasing carbon dioxide concentration.

    But this “CO2 climate sensitivity” is a sham, a mockery, a lie that I personally killed with my Venus/Earth temperatures-vs-pressure comparison, way back in November 2010 (and Curry and her blog readers were among the first I notified, in December 2010, so she should know this by now). The climate sensitivity numbers given in her testimony, above, are easily dismissed by the Venus/Earth comparison: She quotes 3°C per doubling of CO2 for the IPCC narrative, and about 1°C per doubling for the “lukewarmer” stance she champions. But this is the definitive fact: Venus has 96.5% atmospheric CO2, to Earth’s 0.04%; from 0.04% to 96.5% is 11.4 doublings of CO2, and so the Venus atmospheric temperature at a given pressure level–say 1,000 mb, which is the surface pressure on Earth–should be over 33°C higher, in the IPCC scientists’ reckoning, or over 11°C higher in the “lukewarmers” reckoning, than it would be with just 0.04% CO2. But it is not–when corrected for Venus’s closer distance to the Sun, Venus’s temperature is the SAME–not 33 degrees higher, not 11 degrees higher, not even 1 degree higher–as Earth’s.

    Every climate scientist I am aware of–and certainly every one in the debates, like Curry–simply ignores this. And some–like Curry, and the feckless Obama–are so cocksure as to engage in debates (pitiful as they are) on official “climate policies”, when the fact I have just given means no climate policy is called for, at all.


    • steve bickel  


      Doesn’t the albedo come into play for both earth and venus. And earths is so variable how would you compare? And how do you account for the sulpher dioxide versus water vapor clouds? You make it seem like the equations are simple and you figured them our for two planets and yet most people cant figure out earths total energy absorbtion / radiation and relate that to surface temperature because of the complexity (hence the warming lull).



    • David Appell  

      Huffman does ignore the albedos of both Venus and Earth. This makes his calculation worthless.


  2. steve bickel  

    Nice, finally a skeptical view that has some merit via balanced reporting. I am more of an alarmist than skeptic but the skeptics have been hard to talk with because they cite non sense so much of the time. You are refreshing.


  3. Denis Ables  


    Dismissing most skeptical arguments as nonsense is ludicrous, if compared to the alarmist position.

    Do you dismiss the Medieval Warming Period — in the face of the (very) numerous studies showing that the MWP was as warm, likely warmer, and global (all links at co2science.org)? If so, does that mean you also dismiss the studies showing the warmings during this interglacial BEFORE the MWP were also global and even warmer? If you want to argue about the accuracy of the temperature proxies, that would seem to also throw Mann under the bus because he used the same (in dubious ways besides, at least up until the time where the data no longer confirmed his hockey stick. What about the 6,000 boreholes from around the globe which consistently show the MWP to be global? Are you prepared to defend claims that our current warming (such as it is) is outside the range of natural climate variation? Even the IPCC’s latest report uses smoke and mirrors to get as far back as an 800 and 1200 year duration. The IPCC chooses to ignore the warmings prior to the MWP.

    How much faith can you put in the “greenhouse effect” as a valid representation of our open atmosphere? After all, there is no convection from within a real greenhouse. And evidently satellites detect heat escaping to space. What about feedbacks, and what about the fact that co2 capability to impact temperature diminishes as its level increases? Are there any experiment results showing where we are in that cycle? I recall seeing something about co2 having absorbed 50% of the few sun energy bandwidths available to it (all evidently also availeble to water vapor) when it was at 20ppmv.

    Has Monckton’s straight-forward (and transparent) analysis of global temperature made any impact on you? According to RSS data, it’s now 18 years and 5 months with NO additional warming, and if the mean of all 5 global temprature datasets is used in place of RSS, there’s still 13+ years of no additional temperature warming, and that terrestrial data is really dubious! Furthermore, from 1950 to current the rate of increase of temperature appears to be within normal climate variation. What’s to be alarmed about?

    Where is the settled part in this “settled” science? The claim that the missing heat has disappeared into the ocean is not dealt with in any of the computer ;models. Whats more the rate of increase in warming of the ocean is small, if not miniscule, perhaps .5 degree per century.

    Our current warming, such as it is, began – by definition – at the bottom of the LIA in the mid 1600s, NOT in the mid 1800s. That’s 200 years of natural climate warming before co2 began rising , and even the most rabid alarmist scientists have acknowledged that increasing co2 would have had no impact on temperature until about the 1950s. That pushes our current natural warming to 300 years, with considerably more temperature increase than since 1950.

    There seems to be no empirical evidence at all for the AGW hypothesis. Researchers appear to have a decent handle on both temperature and co2 levels across geologic periods, and co2 level has been considerably higher during most of the planet’s existence. There is a strong correlation, but the reverse of what alarmists need, because it shows temperature variation FIRST, and very similar co2 variation hundreds (or more) years LATER. This is likely just the carbon cycle at work. Correlation does not necessarily imply causation, but in this case it would seem to imply that there is not even a correlation over geologic periods showing that co2 is a driver of temperature. Where is the evidence? This would seem to render the AGW hypothesis nothing but casual speculation, not unlike that raggedy fellow on the corner holding a hand written sign claiming the world will end tomorrow.

    Then there are the recent bogus claims by our supposedly prestigious government science organizations, NOAA and NASA. Both (using only terrestrial temperature data) initially rushed to claim 2014 the hottest, when everybody and it is obvious that the difference in global temperatures amongst recent years is miniscule, well within the uncertainty level, so there can be no “winner”. These “science” organizations failed to acknowledge that or to admit that the same bogus calculations applied to satellite data show 2014 was NOT the hottest. No scientist interested in the truth would even consider doing that.

    What about the suspicious revisions of terrestrial temperature data? Earlier data is invariably, revised downward, which, of course, makes current temperatures look warmer. It would be surprising if that’s not FRAUD. Recent raw data from from several temperature stations (each covering large distances) in South America shows a 60 year cooling trend, but the ” revised” data used for calculating global temperature shows a 60 year warming trend. How can that possibly be justified? If the data is that bad, it should have been discarded.

    There’s not time to get into the egregious actions by “scientists”, who, during the past years, feeding (or aspiring to) at the IPCC trough. Those actions should have been sufficient to throw away the research, and ruin reputations.

    In the face of all this, how can anyone claim skeptics are the folks making nonsensical claims? ?


  4. Week in review – science edition | Climate Etc.  

    […] The Brave Judith Curry:  One plus the truth equals a majority [link] […]


  5. Tony Kondaks  

    In your opening paragraph, you describe Professor Curry as someone who is ” respected by the quiet climatologists, not only the so-called skeptics…”

    The reference to “quiet climatologists” suggests that there is room for civility in the discussions on climate change that are, as a rule, often cantankerous and divisive. Recently, I saw a youtube video discussion between Richard Lindzen and Hadi Dowlatabadi, a self-described “consensus scientist.” The discussion was civilized, respectful, and calm. One hopes this is a sign of things to come:



  6. Week in review – science edition | Enjeux énergies et environnement  

    […] The Brave Judith Curry:  One plus the truth equals a majority [link] […]


  7. jae43  

    As many have pointed out: The warming models are all wrong (no increase in temperature for 18 years). Therefore the science the models are based on is wrong. Therefore, there is no demonstrable crisis. Therefore, there is no reason to “do something” at this point.

    It’s really that simple, folks.

    CO2 levels keep increasing; whereas, global temperature does not. Therefore you DO have to question the atmospheric greenhouse gas theory. Or find a plausible reason that CO2 ain’t warming things up. (Plausible, not claptrap like “the ocean is hiding the heat.”)


    • Brian H  

      Because, with an imperceptible delay, it radiates as much as it takes in. The ‘blanket’ analogy is fundamentally flawed. Bogus, even.


  8. Mervyn  

    Distinguished US atmospheric physicist, Dr Richard Lindzen, was so right when he said:

    “Future generations will wonder in bemused amazement that the early twenty-first century’s developed world went into hysterical panic over a globally averaged temperature increase of a few tenths of a degree, and, on the basis of gross exaggerations of highly uncertain computer projections combined into implausible chains of inference, proceeded to contemplate a roll-back of the industrial age.”


  9. Iceman  

    Harry Dale Huffman is correct, there is no greenhouse effect at all. Our atmosphere is wide open to space. He proved it with his comparison to Venus, and further proof is that the same calculation can be made with Titan and checked against data from the Cassini-Huygens probe.

    What also must be challenged is the idea that the ice core records from Antarctica and Greenland are continuous records of past climate that show abrupt changes in and out of ice ages. They are not continuous, but the remnant sections of a larger cycle, sections of ice having cyclicaly melted away, then started growing again.

    The ice age cycle is caused by a change in gravitational pressure, governed by the circumference of the galaxy and the speed of light, at 330,000 years. It also explains the megafauna of the past, like the Woolly Mammoth, and what caused their extinction, increasing gravity, decreasing atmopsheric pressure and temperatures. The Woolly Mammoths thrived 50,000 years ago in warmer temperatures and lower gravity. It is time to throw out an entire dictionary of terms used by the warmists: greenhouse gasses, interglacial, albedo, Holocene, Eemian, carbon pollution, etc. http://www.galacticgravitywave.blogspot.com


  10. Jacqueline  

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